Quarterly Journal of Conc/iology. i 4 1 



obsolete? ; Zona lanuginosa, porifera ; btanchice posticce. 



Hemiarthrum setulosum, Cpr. On stones at low water. This shell 

 externally resembles some of the coarse, ill-defined Acantho- 

 chitons. It forms a transition between Hanleia and the articu- 

 late Chitons. 



Helix ( Hyalina ) Hookeri, Pfr. "Gregarious about and under stones. 

 Occasionally the shell appears to be partly membranous, and in 

 drying, from this cause, the spire is frequently abnormally 

 flattened." 



Siphonaria tristensis, Sow. Abundant between tide-marks, also 

 found at Tristan d'Acunha, and Orange Harbour, Patagonia. 



Lasea rubra, Mont. Rather larger than most northern specimens. 



Lepton parasiticum, Dall. Abundant in the channels leading to the 

 oral aperture of an Echinus ( Tripylus) where it appears to lead 

 a parasitic or commensal existence. The shell is of extreme 

 tenuity and must almost entirely have been enveloped by the 

 soft parts. The dentition resembles the other species of the 

 genus. 



A new genus, Kidderia, of Modiolarcidce is established for a spe- 

 cies found by Dr. Kidder. It differs from Modiolarca in its 

 single anterior muscular scar, the presence of strong nymphs 

 for the subinternal ligament, and in the full development of the 

 cardinal teeth. Modiolarca pusilla, Gould, from Tierra del 

 Fuego, appears to belong to this group. 



Kidderia minuta, Dall. This minute species was found attached to 

 the byssus of My stilus canaliculus. It has also been obtained by 

 Mr. Dall from Orange Harbour, Patagonia. 



Mytilus Magellanicus, Chemn. Found also in New Zealand, and 

 at the Straits of Magellan. 



Mytilus canaliculus, Hanley. The shell of this species closely resem- 

 bles some of the varieties of M. edulis, but the soft parts are 

 quite different. Inhabits also Chili and New Zealand. 



Mr. Dall is now engaged in examining the large collection of 

 Shells from New Zealand, Tasmania, Auckland and Chatham 

 Islands made by Dr. Kershner, the results of which will we 

 hope be shortly published. 



