1885. | Zoölogy. T005 
ZOOLOGY. 
E. Ray LANKESTER’S CONTRIBUTIONS TO A KNOWLEDGE OF 
RHABDOPLEURA.!— The tube is secreted by the disk or epistome, 
is wholly external to the animal shut off into chambers, one for 
each polypide. ; 
The polypides present a body with the disk beneath it, mouth on 
either side under the disk, an arm with tentacles in a double row 
upon it, upon the opposite side of the body from the mouth the 
anus, body shaped like a sack with the intestine coiled and sur- 
mounted upon a stalk placed upon the mouth side. All this 
was known before. Lankester, by sections, demonstrates a space 
between the body wall and the gut wall partially filled with tis- 
sues, probably muscular and connective, which he calls the body 
cavity. The existence of a body cavity had not before been 
shown. Also upon the lower side of the main stack of the arms, 
near their base, L. finds a small ciliated pupilla which he thinks 
may be an osphradium. The lophophoral arms he considers the 
genetic equivalents uf the ctenidia of Mollusca. 
He demonstrates for the first time a sort of cartilaginous meso- 
blastic skeleton supporting the arms and the contractile cord. 
Finds the testis, not found by Allman or Sars, a blind sack open- 
ing by a special pore; this gonad belongs to Lankester’s idiodinic 
gonads, and is not at all a modified nephridium. Allman’s stat- 
oblasts are considered by Lankester to be undeveloped buds ; 
buds which from some debility failed to burst through the chitin- 
ous tube and mature. In the absence of information upon the 
embryology, the affinities of Rhabdopleura cannot be definitely 
spoken upon. If the disk is the homologue of the epistome of 
Bryozoa, then it cannot be the homologue of the molluscan foot, 
since its position is dorsal, not ventral, and we may consider it 
‘homologous with the mantle, as suggested. by Allman.—Henry 
Leslie Osborn 
THE LARGE IGUANAS OF THE GREATER ANTILLES—The Jguana 
e M. cornutus is said to be from the same island, but the 
- authors of the Erpetologie Generale consider this uncertain. It 
IS certain that some large lizards having a horny tuberosity on 
the muzzle inhabit that island. : — 
Cyclura, as hitherto defined, does not, in the writer’s opinion, 
differ from Ctenosaura, thé species of which inhabit Mexico 
1 Quart. Journ. Mic, Soc., 1884, p. 622. 
