412 MR. F. CHAPMAN ON THE 
HETEROSTEGINA DEPRESSA, d’ Orbigny. 
This species occurs practically in every dredging round 
Funafuti. It is usually the megalospheric form (A) which its 
found in such abundance. Form B has only been found at one 
locality at “To,” S. of Fuatatu, 60 fathoms. Since writing the 
note on this species from Funafuti previously published *, the 
author has measured the megalosphere and the microsphere with 
the following result :— 
Form A.—Specimen from N. of Pava, 36 fathoms ; megalo- 
spheric chamber with diameter of 125 p. 
Form B.—Specimen from 8. of Fuafatu, 60 fathoms: micro- 
spheric chamber with diameter of 65 u. 
CycLocLyPEus CaRPENTERI, Brady. 
In the former paper, above mentioned, the presumably numerous 
and half-grown microspheric forms of C. Carpentert there referred 
to have on further investigation proved to be variant forms of 
the megalospheric type. My attention was kindly drawn to this 
by Mr. J. J. Lister, who noticed the exceptionally large measure- 
ments quoted for the microspheric form of the species. Since 
then, on further examination, it appears that the megalosphere 
ig not constant in size, some specimens having the primordial 
chamber much smaller than others. 
The only undoubted example of a microspheric shell which the 
writer has been able to obtain amongst the numerous specimens 
from Funafuti is that which has already been figured in section 
in the former papert as Cycloclypeus with a Heterostegine 
commencement. The section, on careful examination, proves to 
have been cut, most fortunately, quite accurately through the 
median plane; and the interesting spiral development of the 
earlier chambers may be quite typical of all microspheric forms 
ot the species (see J. c. fig. 2). The writer looks forward to corro- 
boration on this point. This spiral commencement may be 
compared with parallel forms in the porcellanous group, as im 
Orbiculina and Orbitolites marginalis. 
The measurements of the megalosphere and microsphere for 
this species give the following results :— 
Form A, megalospheric chamber with the diameter of 260x 
240 « (average example). 
Form B, microspheric chamber with a diameter of 40 p. 
* Journ. Linn. Soc., Zool. vol. xxvili. p. 19. 
+ Ibid. p. 27, pl. iu. fig. 2. 
