1879.] MR. E, A. SMITH ON MOLLXJSCA FROM JAPAN. 181 or lesser extent, ofthe dark pectoral blotch coTcred with light spots: — one, 12g inches long, from the Propontis ; another, 9| inches long, if'rom Dalmatia ; a tliirfl, of the same size, from Naples ; and a fourth, 7i inches in length, from Sicily. As no structural difference is observable between T. pceciloptera and T. hirundo, except such as may be due to age, I think we are justified in considering the former the immature of the latter ; while the immature colours may be continued (although less decidedly) to the adult age, this difference being restricted to the inner side of the pectoral fin. Whether Thompson's specimen was T. hirtmdo or T. lineata is open to grave doubt. He says : — " 10 dorsal spines .... lateral lines spinous ;" and as to colours, " I have little doubt that when recent it would in coloio-have corresponded. So I conclude it did not cor-respond when he received it from Mr. Ball, who obtained the single example, 2 inches in length, from among some sprats captured at Youghal, in Ireland. A Tri(/la possessing ten dorsal spines and a spinous lateral line is unlikely to be T. pceciloptera, which has nine dorsal spines and a smooth lateral line. EXPLANATION OF PLATE XVIIL Trigla hirimdo, from a specimen in the author's collection obtained near Southend : a. Stomach and cacal appendages ; h. Air-bladder ; c. Pectoral fin (inner side). 11. On a Collection of Mollusca from Japan. By Edgar A. Smith^ F.Z.S., Zoological Department, British Museum. [Eeceived January 28, 1870.] (Plates XIX., XX.) A large collection of Japanese Mollusca, containing very many new and most interesting forms, has been presented to the British Museum by Dr. J. Gwyn Jeffreys, F.R.S., with his wonted liberality. It is a most valuable addition to the series of species from the same region w-hich was placed in the national collection a few years ago by the same gentleman. That series, of which a brief account of the Gastropoda only appeared in the ' Annals and Magazine of Natural History' for 1875, was dredged by Capt. H. C. St. John, of H.M.S. ' Sylvia.' The specimens now to be considered were derived from the same source ; and the highest praise must be accorded to Cajit. St. John for the excellent manner in which they have been collected and preserved. Most of them are from the region of the Goto islands ; and to save the continual repetition of the longitude, latitude, and depths of the various stations, a list of them with consecutive numbers is appended below ; so that for the locality of each species only the number of the station will be quoted.