that in the English species there are five lateral tentacles arranged in 

 two series, three in the region of the operculum, two anteriorly placed 

 with a distinct interspace between. In our species the lateral ten- 

 tacles are six in number equidistant, the anterior ones slightly longer, 

 diminishing in length posteriorly. (PI. II, Fig. 9 A) marginal ten- 

 tacles enlarged. 



MARGARITA HELICINA Phipps 

 PI. II. Fig. 10. Diameter 6 mm. 



This exquisite , shell is usually found on the large lamanaria in 

 March. Its perfect symmetry and beautiful purple iridescent surface 

 easily render it one of our most attractive shells. It is a common shell 

 in Iceland, Spitzbergen, Scandinavia and Northern regions of Great 

 Britain. In collecting numbers of specimens one quickly recognizes 

 two forms; a large globular form and a smaller depressed shell with 

 flaring aperture. This form I described many years ago under the 

 name of Margarita campanulata, supposing it to be a new species. 

 In studying large numbers collected at Ironbound Island, Maine, I 

 am convinced that the campanulate form represents the male of the 

 species. Forbes and Hanley detected this form among specimens 

 of Margarita helicina. In their classical work they say "There are 

 two forms of this shell so apparently distinct at the first glance that we 

 hesitate to regard them as belonging to the same species. The one is 

 peculiarly oblique and depressed, a very expanded outer lip and the 

 rest of its features modified to correspond with the general contour; 

 the other is far more globular." In our species the muzzle is deeply 

 crenated, the ends strongly ciliated (Fig. 10 A). The eyes are 

 pedunculated and on the inside, at the base of each tentacle, is a small 

 tubercle. The tentacles are long and larger than the lateral tentacles, 

 these are five in number becoming shorter towards the tail except the 

 middle one which is markedly shorter than the others. In Forbes 

 and Hanley the lateral tentacles are described as being in two groups, 

 three in the forward group, with quite an interspace and two behind. 

 The animal of the English species is described as orange color, while 



