350 Mr. A. S. Woodward on Rhaphiosaurus. 
pigment-circulation. The discharge of pigment, however, is 
something different and possibly capable of a very different 
interpretation. 
Is the discharge normal or abnormal? Is it a result of 
extraordinary conditions under which the animal is placed in 
confinement in our aquaria, or is it an habitual mode of pro- 
tection? It seems to me that the latter interpretation will 
best satisfy our limited knowledge; and although when the 
bracts are broken the discharge is more voluminous, since the 
glands are wholly emptied of their contents, the method of its 
discharge shows it to be a function which is perfectly normal. 
It seems to me that we have in these “ glands ” the homo- 
logues of nematocysts, the thread of which is wanting and the 
cells of the interior of which have degenerated or rather 
specialized into pigment-bodies, instead of functioning as an 
urticating-thread. These modified nematocysts throw off a 
coloured fluid which, while it serves in a similar way in pro- 
tection or in killing its prey, bears little morphological like- 
ness to the well-known lasso-cell. 
XLV.—On the so-called Cretaceous Lizard, Rhaphiosaurus. 
By A. SmitH Woopwarp, F.G.8., F.Z.S., of the British 
Museum (Natural History). 
In 1840 Prof. Sir Richard Owen described a small portion of 
mandible from the Lower Chalk of Cambridgeshire under the 
name of Ihaphiosaurus *, regarding the fossil as referable to 
a Lacertilian Reptile and provisionally associating with it a 
series of undoubted Reptilian vertebree from the Lower Chalk 
of Burham, Kent. Ten years later the vertebree proved to 
pertain to a distinct generic type named Dolichosaurus T ; and 
the original jaw thus remained as the sole evidence of the 
existence of Rhaphiosaurus. In 1865 Prof. Seeley { stated 
incidentally that the specimen so determined probably belonged 
to a fish ; and still more recently the genus has been recorded§ 
as one requiring further elucidation. 
* R. Owen, “ Description of the Vertebral Column &e. of a small 
Lacertine Saurian from the Chalk,” Trans. Geol. Soc. [2] vol. vi. (1840) 
p. 413, pl. xxxix. fig. 5. Rhaphiosaurus subulidens, Owen, Brit. Assoc. 
Rep. 1841, p. 190. #. duciws, Owen, in Dixon’s ‘Geol. Sussex’ (1850), 
p. 385, pl. xxxix. figs. 1-3. R. subulidens, Owen, “ Foss. Rept. Cret. 
Form.” (Pal. Soc. 1851), p. 19, pl. x. figs. 5, 6. 
+ R. Owen, “ Foss. Rept. Cret. Form.” (Pal. Soe. 1851), p. 22. 
t H. G. Seeley, Ann. & Mag. Nat. Hist. [5] vol. xvi. p. 146. 
§ Smith Woodward, “ A Synopsis of the Vertebrate Fossils of the 
English Chalk,” Proc. Geol. Assoc, vol. x. (1888) p. 281. 
