rg10.]. J. Rrrcenie: HAydrotds of the Indian Museum. 19 
Locatity: R.I.M.S. ‘‘ Investigator ’’ Station 241, lat. 10° 12’ 
N., long. 92° 20’ 30” E., between the Andaman and Nicobar 
Islands ; depth 606 fathoms. 
This is a very well-defined species, easily distinguished by the 
peculiar arrangement of its internodal ridges, by its large sarcothece, 
and by the sinuous margin of its hydrothece. 
Type in the Indian Museum, Calcutta. 
Lytocarpus pennarius (Linnzeus). 
(Bissiy sie. 11.) 
Linneeus, C., 1758, p. 813; as Sertularia pennana. 
Allman, J. G., 1883, p. 42, pl. xiv; as L. secundus, Kirchen- 
pauer.! 
This species is represented by a solitary much-weathered 
colony 56 cm. long, with a large basal mass of matted rhizoids ; 
and by a few unattached branches. While the specimens agree 
with Allman’s description, the following additional observations 
have been made. ‘The hydroclades spring alternately from the 
anterior tube of the fascicle, and sometimes reach a length of 18 mm., 
three times the recorded length of those in the ‘‘ Challenger ’’ 
collection. The hydroclade-bearing process is accompanied by 
three large, scoop-shaped sarcothecee, two of which are anterior— 
one on the process, the other proximal to it—while the third lies 
on the inner side of the angle between process and stem. 
The hydrothece agree closely with the description of Mark- 
tanner-Turneretscher (1890, p. 273). The margin bears a promi- 
nent anterior tooth, and about four indefinite sinuations on each 
side. The intrathecal ridge is short, slants upwards, and often 
terminates in a prominent knob, while the internodal ridges are 
much more insignificant than those in Allman’s figures. The 
mesial sarcotheca is adnate for little more than half the height of 
the hydrotheca and a connection exists between the distal portion 
of its cavity and that of the hydrotheca. The supracalycine sar- 
cothecze are asymmetrical, that on the side of the hydrotheca facing 
inwards towards the centre of the stem being very large and bowl- 
shaped, while the other has a diameter scarcely half that of its 
fellow (pl. iv, fig. 11). This difference may in part account for 
the discrepancy between the sizes of the sarcothecee as figured by 
Kirchenpauer (1872) and by Allman, the latter having figured the 
hydrotheca from the stem side, the former from the opposite. Not- 
withstanding, however, the hydrothece of our specimens, as did 
those of Marktanner-Turneretscher, agree more closely with Kir- 
chenpauer’s diagnosis of Aglaophenia crispata than with that of 
A. secunda, to which Allman referred his specimens. 
1 The identity of the ‘‘ Challenger ’’ specimens with the Linnean species bas 
been established by Billard (1908, p. 3) after comparison of the former with the 
Linnean type specimen in the British Museum. 
