290 BULLIDA. 
B. catena, Montagu et Auct. 
B. catena, Zool. Journ. iii. p. 337. 
Philine catena, Brit. Moll. iii. p. 545, pl. 114. E. f.6, 7; (animal) 
pl. U.U. f. 4. 
The animal is an elongated oval; the upper disk, as in the 
tribe, is essentially an integral plate, though the skin is broken 
into two apparently well-separated lobes; the anterior one is 
the longer and narrower oval, and shows no trace of eyes or 
tentacula; the posterior is broader and shorter, and encloses 
within the skin an elegant, clear, white clypeiform shell, 
marked with close transverse catenated striz; the posterior 
extremity of this lobe is digitated. The pedal disk extends, 
without a break, the whole length of the animal, the sides 
being well reflexed on the upper lobe, giving that surface the 
quadrilobated aspect of the tribe. Between the two disks, 
just under the upper one, is a slight inflation, the repre- 
sentative of the head, beneath which is the vertical buccal 
orifice. 
For the anatomy, I refer to my accounts of the Bulla 
hydatis and Bullea aperta; it is the prototype im miniature 
of those species, as far as can be judged in so diminutive a 
creature. I couple the B. hydatis with the B. aperta, as the 
internal organs of the animals, though of so different an exte- 
rior, are essentially identical. The gizzard in this animal pre- 
sents some difference, being an elastic muscular cylinder cased 
with three similar-shaped white testaceous trapezoid plates, 
pointed at the axes. The colour of the upper disk is a yellow 
ground, closely aspersed with light red-brown minute points, 
mixed with a very few lines and blotches of similar colours, 
and some specks of sulphur-yellow ; the pedal disk is powdered 
throughout on a pale yellow ground with rather mtense 
minute yellow points or small streaks. The animal inhabits 
the littoral zone, at Exmouth, but is rare amongst alge in 
the sheltered pools; it is by no means sluggish, and delights 
in swimming. Longitudo 54%, latitudo et altitudo circa ;%> 
uncle. | 
This is a reproduction, perhaps not a disadvantageous one, 
of an account of this animal and the Bullea punctata which 
