26 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
seem to warrant the establishment of a new family Aceridte distinct 
from the Bullidte. 
Pleurophyllidia Loveni.* — Mr. J. T. Cunningham reports that a 
single specimen of this rare Opisthobranch has been taken off the north 
of the Eddystone. Two specimens from the British area have been 
long known, and Mr. Holt lately took two from fishermen’s haddock- 
lines in St. Andrews Bay. 
Occurrence of Hancockia at Plymouth.^ — Mr. F. W. Gamble 
records the discovery of a second British example of this Nudibranch ; 
the only other specimen was taken at Tor Bay. Four specimens taken 
at Naples were described by Trinchese under the name Goria. The 
Plymouth specimen is apparently intermediate between H. eudactylota 
and G. rubra. 
Reproductive Apparatus of Aplysiidse.J — Sig. G. F. Mazzarelli finds 
that all the ova which are dehisced separately or precociously into the 
small hermaphrodite duct, and which mix with the seminal current, are 
destroyed in Swammerdam’s vesicle. At different times, the semen and 
the ova pass along the same path — through the small hermaphrodite duct, 
the chamber of fertilization, the efferent duct, and the dorsal genital duct. 
The semen which is emitted is never pure, but mixed with ova, lecithin, 
and fatty corpuscles, &c. In the large hermaphrodite duct there are 
two distinct paths, one for the genital products, the other for the ferti- 
lizing elements. With the anterior portion of the efferent duct a gland 
is associated which lubricates the passage like a prostate gland. The 
vesicle of Swammerdam is not connected with the efferent duct, but is 
rather a vaginal diverticulum between the vaginal and the copulatory 
duct. In copulation the penis penetrates into the vaginal duct, and the 
semen is directed into Swammerdam’s vesicle. There it is purified, aud 
thence it passes by the copulatory duct to accumulate in the copulatory 
pouch. Swammerdam’s vesicle is a filtering sac. The ova are fertilized 
in a fertilizing chamber, into which spermatozoa pass by the “ duct of 
Cuvier” ; the ova are surrounded with albumen from the albumen-gland, 
and are united in packets by the mucous secretion of cells lining part of 
the efferent duct. The packets are united in a string in the spiral 
portion of the efferent duct by the secretion of the nidamental gland. 
The reproductive apparatus of Aplysiidse has morphological affinities 
with that of Cephalopods ; the large hermaphrodite duct corresponds to 
that of other Tectibranchiata ; the fertilizing chamber corresponds to 
the posterior end of the hermaphrodite duct of other Tectibranchiata ; 
the nidamental gland of Aplysiidae is a new formation without homo- 
logue ; the copulatory pouch of Aplysiidse is not homologous with the 
copulatory pouch of other Tectibranchiata, it probably corresponds to 
the primitive nidamental gland of the Aplysiidaj. The reproductive 
apparatus of Aplysiidse is more evolved than that of the Cephalaspidae, 
and is more differentiated than that of Notospideas, excepting perhaps 
Umbrella and Tylodina. In Aplysia punctata, the reproductive apparatus 
persists in a relatively primitive condition. 
* Journ. Mar. Biol. Ass., ii. (1891) pp. 194 & 5. 
t Tom. cit., pp. 193 & 4. 
J Atti It. Accud. Sci. Napoli, iv. (1891) pp. 1-50 (4 pis.). 
