430 Dr. F. Miiller on some peculiar Structures 



The young with brown cross bands : the first is horseshoe- 

 shaped, and encircles the occiput^ each branch advancing to the 

 eye ; there are two irregular brown spots within its concavity : 

 the second band occupies the posterior two-thirds of the neck : 

 the third and fourth across the middle of the trunk : the fifth 

 across the sacral region. Tail with five brown rings. These 

 bands and rings are broader than the interspaces of the ground- 

 colour, which is brownish yellow. 



In the adult only the brown edges of these bands remain ; so 

 that there is one pair of brown cross bars on the neck, and three 

 pairs on the trunk, the space between the bars being of the 

 ground-colour. The horseshoe-shaped band on the occiput re- 

 mains single ; but the markings on the head are more defined 

 than in the young one, viz. a pair of brown rings on the crown 

 of the head, one cross band between the eyes, and two on the 

 snout ; a longitudinal streak runs from the eye to the nostril. 

 Lower parts white ; a group of indistinct brown dots on the 

 elbows and knees. 



I am indebted toR.T. Riddell, Esq., for two specimens of this 

 species : one is adult, 5^ inches long, the length of the tail being 

 2^ inches ; the other, young example is 3 inches long, tail 

 1;^^ inch. They were collected at Hydrabad, Sindh, where the 

 species is unjustly reputed to be venomous. 



XLVIII. — On some peculiar Structures in the Seminal Fluid of 

 lanthina. By Fritz Muller of Desterro*. 



It is but rarely that pelagic animals find their way into the arm 

 of the sea which separates the island of Santa Catharina from 

 the mainland of South America. Amongst these visitors, which 

 are sometimes absent for several years together, are two species 

 of lanthina, which usually make their appearance as attendants 

 on swarms of Velellce. One of them with a more acute spire (/. 

 exigua, Lam.), of which only a few females have once been seen, 

 bears its eggs upon the frothy appendage of the foot : the other, 

 which has been repeatedly found, has a flatter spire (/. pallida, 

 Harv.), and is viviparous; in this I ascertained that the frothy 

 appendage occurs in precisely the same manner in both sexes. 



In the seminal fluid of the latter species there are some very 

 peculiar structures, to which I would call the attention of visitors 

 to the Mediterranean and others who may have the opportunity 

 of examining this remarkable Mollusk. It is very probable that 

 such an opportunity may not occur to me again for years ; and 



♦ Translated by W. S. Dallas, F.L.S., from Wiegmann's ' Archiv,' 1863, 

 p. 179. 



