THE ANNALS 



AND 



MAGAZINE OF NATURAL HISTORY. 



No. 77. OCTOBER 1843. 



XXVIII. — Notice of a British species of Callioppea, D^Orhigmj, 

 and of Four new species of Eolis, with observntions on the De- 

 velopment and Structure of the Nudibranchiate Mollusca. By 

 Joshua Alder and Albany Hancock, Esqrs.* 



The genus Callioima was established by D'Orbigny for a small 

 mollusk found near Brest, and published in Guerin^s ' Magasin 

 de Zoologie/ It is distinguished from Eolis by having only two 

 tentacula, and also (according to D'Orbigny) by the longitudinal 

 arrangement of the dorsal papilLne. The latter distinction, how- 

 ever, does not hold good, and a better may be had in the arrange- 

 ment of the vessels of the gastro- vascular system, described by 

 Milne Edwards in a second species found on the shores of the 

 Mediterranean. We have now the ])leasure of announcing a 

 third species from the Devonshire coast, being the first that has 

 occurred in Great Britain. 



This beautiful species, which we have named Calliopaa dendri- 

 tica, is about a quarter of an inch long, with seven or eight 

 rows of large, elliptical, dark green papillse on each side of the 

 back, three in each row. The general colour of the body is a 

 pale pellucid grass-green : two dark green lines run down the 

 sides of the back, sending off branches of the same colour, which 

 ramify in all directions, and give the little animal a peculiarly 

 elegant appearance. These dendritical markings are caused by 

 the vessels of the gastro-vascular system of Milne Edwards, of 

 which we shall have occasion to speak afterwards. It was fomid 

 on sea-weeds at low-water mark in Torbay, and appears to be 

 gregarious. Nearly one hundi'ed specimens were sent us from 

 thence by Mrs. Wyatt. 



Eolis stipata. — This species is also from Torbay, where we 

 obtained it from the produce of a day's dredging in September 

 last. It is about a quarter of an inch long, rather broad and de- 

 pressed, and of a bright yellowish green on the body with short 

 tentacula, and about nine rows of bluish-green papilla covering 

 the whole of the back. This species belongs to the section con- 



* Read before the Natural History Section at the Cork Meeting of the 

 British Association, and communicated by the Authors. 

 Ann, ^ Mag. N. Hist, Fb/. xii. B, 



