ANTIOPA CRISTATA. 



outline, terminating at the sides in obtuse angles scarcely produced. The colour is transparent 

 white or yellowish. 



This splendid animal was dredged in Torbay, by Dr. Battersby, whence it was sent us 

 through the kindness of Mrs. Griffiths. We have since met with it in Cornwall and North 

 Wales, and Mr. Moggridge and Mr. Gosse have each obtained a specimen on the shores of 

 the Bristol Channel. It appears, therefore, to be pretty generally diffused on the south- 

 western shores of our island. It is one of the few species we possess common to England and 

 the Mediterranean, and is probably a southern form that here reaches its northern limits, as 

 in the Mediterranean, where it is more common than with us, it attains a larger size. The 

 specimens we dredged in the Menai Straits, were scarcely more than half the size of those on 

 the southern coast. 



This is a very active animal, moving about with great grace and elegance. The branchial 

 papillae are then in constant motion, and when seen on a dark ground, their brilliant tips stand 

 out conspicuously, and appear like a cluster of gems. We have observed an aperture at the 

 end of each papilla, visible with a common pocket lens, which, when the animal is in a lively 

 state, is frequently opened and closed alternately : when open, the apex assumes a rounded 

 outline, but it terminates in a sharp point when the aperture is closed : the latter, is the usual 

 form when the animal is at rest. This action is probably connected with the discharge of 

 urticating filaments, as in the Bolides, but we could not detect anything issuing from the 

 aperture at the time. 



The spawn of this species, for a drawing and description of which we are indebted to 

 Mr. Gosse, presents some peculiar features. It consists of a transparent gelatinous thread, 

 deposited in tortuous undulations, which Mr. Gosse aptly compares to a succession of figures 

 of 8. These are arranged in the usual spiral form. The ova are in single series, and are 

 transparent globules, appearing at first about two thirds filled with opaque white specks, in 

 the form of a crescent. "About five days after deposition," Mr. Gosse informs us, cc the white 

 specks in the globules had filled the whole interior," and on examination under a microscope, 

 " each globule was seen to be a chorion of gelatinous membrane containing more than sixty 

 active little nautiloids." Usually the ova of the Nudibranchs are crowded together in numerous 

 rows throughout the gelatinous envelope, each egg having a single embryo, or at most three 

 or four. Here, however, there is only a single row of eggs, but the apparent deficiency of 

 numbers is made up by each egg containing numerous embryos : the whole amounting, 

 according to Mr. Gosse's calculation, to 45,000.* 



Fig. 1, 3. Side and back views of Antiopa cristata. 



2. Under side of the anterior portion of the same. 



4. Two of the papillae. 



5. Dorsal tentacles with crest. 



6. Spawn. 



7. A portion of the spawn enlarged, shewing the arrangement of the eggs. 



* See 'A Naturalist's Rambles on the Devonshire Coast/ p. 325. 



