96 Messrs. M^Andrew & Forbes on new or rare British Animals. 



Head and antennae pale. 



Thorax greenish yellow, the front part broadly ferruginous, 

 sprinkled with cinereous ; legs vinous red, with pale spots. 



Abdomen pale greenish yellow. 



In the collections of the British Museum and W. W. Saunders, 

 Esq. 



This fine insect is easily distinguished from Act. Selene by its 

 peculiar greenish yellow colour, the flexuous external striga, the 

 want of the white band on the prothorax, the great length of the 

 tails, and the more rounded anterior wings. 



XIT. — Notices of new or rare Bintish Animals observed during 

 Cruises in 1845 and 1846. By Robert M'Andrew, Esq. 

 and Professor Edward Forbes*. 



[With a Plate.] 



I. Species of Testaceous Mollusca, new or new to Britain, from 

 the seas around the Zetland islands. 



1. Trochus formosus, sp. nov. T. testa pyramidata, anfractibus 7, 

 planis, nitidis, albis, spiraliter costatis, costis in ultimo anfractu 

 sex, costa superiori crenulata; basi imperforata, in medio Isevi, 

 prope columellam sulcis tribus cincta; apertura quadrangulari. 

 Animal album, oculis nigris. — Breadth at base J an inch ; height 

 the same. PL IX. fig. 1. 



This beautiful Trochus resembles T. ziziphinus in form and 

 habit. The whorls are slightly convex, smooth, shining, white, 

 and not covered by an epidermis. The body-whorl is encircled 

 by six spiral ribs, the uppermost crenate, the next fine and smooth, 

 the third and fourth thick and distant, the two lowermost close 

 and fine. The upper whorls are encircled by three spiral ridges, 

 those of the apex all crenate. The whorls are seven. The base 

 is imperforate, slightly convex, smooth in the centre, with three 

 spiral furrows round the columella and one round the margin. 

 The mouth is quadrangular. 



The animal is entirely white, except its eyes, which are black. 

 It has long, linear, cirrhated tentacula. The eyes are borne on 

 sus-tentacula at their outer bases. The capital lobes are partially 

 developed and abbreviated. The lateral lobes are plain, and the 

 sides furnished with six simple long cirrhi, which are usually 

 carried closely appressed to the shell. The operculum is very 

 pale. 



The only British shell with which this Trochus could be con- 

 founded, is the variety Lyonsii of T. ziziphinus. But indepen- 



* Communicated to the Natural History Section of the British Associa- 

 tion at the Southampton Meeting, September 1846. 



