ADDITIONS TO "BRITISH CONCHOLOGY." 



(Continued from vol. 9, page 33S). 



By J. T. MARSHALL. 



Huiimidas H. and A. Ad. — The colourless shells of this genus are 

 most difficult to discriminate and to assign to specific limits. The 

 number of whorls in the same species sometimes varies in number, and 

 they nearly all have a way of putting on a pseudo-adult appearance 

 which is misleading. The chief point of specific distinction is in the 

 general contour of their shells, and this requires some experience 

 and a critical eye to determine. One pretty sure guide appears to be 

 the microscopic examination of the tip of the spire or nuclear whorls, 

 but hitherto this has not been generally adopted for want of a system. 

 The Rev. R. Boog Watson, in the " Challenger " Report, seems to 

 have been the first to make practical use of this character in 

 diagnosing the Eulimidae, and in the many new species which he 

 describes in that Report he has adopted a measurement of the 

 embryonic whorls which is very ingenious and thoroughly practicable. 

 There is a marvellous variation in these embryonic whorls and the 

 extreme tip of the Eulimidae when viewed microscopically, and con- 

 chologists are much indebted to the Rev. R. Boog Watson for 

 reducing this apical form of measurement to a system. The number 

 of new species of the Eulimidae was a feature of the "Challenger" 

 Expedition, and quite as many were dredged in the "Porcupine" 

 Expedition, a large number of which have yet to be described. With 

 regard to the parasitic or quasi-parasitic habits of Eulinia, Mr. 

 Watson has found them "constantly, sometimes four or five together, 

 among the spines near the vent of Echinus esculentus" and Professor 

 Sars has found E. philippii inside Holothuria intestinalis. 



E. polita L. — Immature specimens of this and E. intennedia 

 have the same proportions up to a certain period of growth, but the 

 upper whorls in E. polita are usually pinched in, the profile of the 

 spire being thus slightly concave instead of regularly conical. The 

 embryonic whorls are also similar, but both vary in sharpness; they 

 can be seen in the young only, the apex being seldom or never present 

 in the adult. A dwarf form, from Guernsey and the Minch, does not 

 exceed half-an-inch in length, the size of adult E. intermedia; but 

 the latter has a smaller mouth and is not so callous on the pillar. 



E. intermedia Cant. — 20 to 90 fathoms. Scilly Islands, Penzance, 

 Torbay, Connemara, Bantry Bay, and off Glenelg 90 f. Also in the 

 Shetland- Fccroe Channel, 570 f. (Triton)! 



Var. rubrotincta Jefifr. — Scilly Islands, 40 f. (Burkilland J.T.M.); 

 Land's End; off Fermain Bay, Guernsey, 12 — 18 f. ; Berehaven; 

 Lamlash, 12 f.; Arran, 25 f. ; Loch Broom, 20 f.; the Minch, 20 — 3of.j 

 Vidlin Voe and Hascosey Sound, E. Shetlands, 8 — 10 f. 



