CllUSTACEA. 
621 
Nat. Hist. xix. p. 46, in the branchial cavity of BactyUyptcrus volitans. Two 
other marine species arc known at present, A. imrimrcm (Risso) and A. 
gantens (Lucas), both from the Mediterranean. The freshwater species, 
A. coregonif is not confined to Sweden, Hermann’s A. deliMnus being the 
same (Thorell, 7. c. pp. 47-49). This is a reproduction of the original memoir 
briefly alluded to in Zool. Record, ii. pp. 311, 365. 
Lamippe pi'oteus, sp. n., Claparede, Ann. Sc. Nat. viii. pp. 23-28, pi. 6, 
Naples, in the cavity of Lohularia digitata. The genus was formed by 
Bruzelius, and it appears to come nearer to Tolyclinophilus than to any other. 
The shape of the animal changes like that of a Gregarina, which is caused 
by partial contraction of the subcutaneous muscular layer. There are two 
pairs of antennro and two pairs of feet, two rudimentary mandibles, one 
single red eye. ’Fho hinder extremity is forked, and each branch furnished 
with five bristles similar to those of the larvfc of Lepas. The digestive ap- 
paratus is simple. There are two small orifices on the ventral side of the 
animal, in the male as well as female ; the sexes are similar also in the other 
external characters, and only to bo distinguished by the inner sexual organs. 
Splanclmotrophus hrevipcs (Hancock k Norman), found by R. Bcrgh in a 
now yEolidian mollusk (genus f}<ilvina from the Kattegat) ; also ho was not 
fortunato enough to find females. Ho thinks tho genus may bo better placed 
Avith tho Gnathostoma \^Copcpoda]\h^n Avith tho Chondracanthina. Naturh, 
Forenings vidensk. Meddel. Kjobenha\-n, 1806, pp. 120, 124, and 125. 
GIRRIPEDIA. 
Balanid.®. 
With regard to the muscles of the Balanidse, F. Muller, 
in opposition to Mr. Darwin, thinks that the depressores tergi 
alone keep the opercular pieces down, so as to close the aperture, 
and that they are elcA^ated, not by the depressores laterales, 
hut simply by the protrusion of the whole body; this view is 
founded on a close examination of the points of attachment of 
these muscles in Tetraclita porosa. Arch. f. Ntrgesch. xxxiii. 
pp. 358, 359, note, pi. 8. figs. 52, 53. 
Fecundation. The Balanidse are generally presumed to be 
self-impregnating hem aphrodites. However, Fritz Muller 
states some cases which render it probable that one individual 
is fecundated by another : first, Darwin himself mentions a case 
of a Balanus balanoides with rudimentary penis, which never- 
theless contained well-developed larvie (Balanidse, p. 106) : 
secondly, Muller once observed a living B. armatus protruding 
its penis ontside of the shell, and moving it as if searching for 
another individual ; he says that if in this situation sperma- 
tozoa should be evacuated, these would be kept far away from 
the body of this individual by the continuous movement of the 
cirri. But the most important observation is that of a hybrid 
specimen: among a great number oi Balajius improvisus,y 2 cr. 
assimilisj one specimen struck him by its reddish colour ; on 
closer examination it proved to agree, in the form of the aperture, 
