ACANTHOCEPHALA, GEPHYREA. 
641 
armaria ) ; longicollis, sp. n., pi. xiii. fig. 13 {Strepsilas interpres, Larus 
ridihundm ) ; striatuSy G., p. 473, pi. xiii. fig. 13 {Carlo cormoranus). E. 
strumosus, Rud., figured in McIntosh’s “ Mar. Inv. St. Andrews,’* pi. 
vii. fig. 18. 
IX. GEPHYREA. 
1. Graff, L. Anatomie des Chcetoderma nitidulurriy Lovdn. Z. wiss 
Zool. xxvi. pp. 166-192, pis. xi.-xiii. 
2. Koren, J., & Danielssen, D. C. Bidrag til de norske Gephyrecrs 
Naturhistorie. N. Mag. Naturv. xxi. pp. 108-138. 
3. Selenka, E. Eifurchung und Larvenbildung von Phascolosoma 
elongaturriy Kef. Z. wiss. Zool. xxv. pp. 442-460, pis. xxix. & xxx. 
(abstr. Arch. Z. exper. iv. pp. Iv.-lviii.). 
4. Th^el, H. Recherches sur \e Phascolion {Phascolosoma) stromhi 
(Mont.) Sommaire. Bihafig till Sv. Ak. Handl. iii. No. 3, pp. 1-7 ; 
J. Zool. iv. pp. 318-324. 
6. . Etudes sur les Gephyriens inermes des mers de la Scandinavie, 
du Spitzberg et du Greenland. L. c. No. 6, pp. 1-30, pis. i.-iv. ; J. 
Zool. iv. pp. 366-390, 474-488, pi. xiv. 
Anatomy, Evolution, &c. 
Koren & Danielssen (2) ha/e ascertained several important facts in 
the anatomy of SipuncuUdcc (especially Phascolosoma). The “ dermal 
corpuscles ” are slime-secreting organs. The vascular system (which is 
wanting, with the tentacles, in Onchnesoma and Tylosoma) is homo- 
logous with the aquiferous system in the Holothuriidm. The segmental 
organs have no internal orifice and are secretory organs (“ primordial 
kidneys”). Eggs and spermatozoa are developed in peculiar organs, 2 
coeca, which afterwards, when the evolution of the sexual products is at 
an end, disappear completely, but detached portions of the ovaries, &c., 
may be found floating in the body cavity and develop their eggs there ; 
in Sipunculusy the eggs may be pressed into the channels of the skin 
through the slits, by the means of which these channels communicate 
with the body cavity, a circumstance which probably has misled former 
observers. Males are much rarer than females. Compare also the 
special anatomical account of Phascolion stromhi, by Th^el (4). 
Graff (1) has made an anatomical investigation, by means of nume- 
rous transverse sections, of Chcetoderma. This genus (considered, with 
Th^iel (5), as the type of a special family) agrees with Priapulus in its 
short proboscis, straight (not convoluted) intestinal tube and terminal 
vent, and in the wanting oral tentacles and segmental organs. The depo- 
sition of carbonate of lime in its dermal spines recalls the Echinoderms, 
while the arrangement of the muscles is suggestive of the Nematoda, and 
the nervous system of the Turhellaria ; the retractile terminal gills and 
the mode of formation of the eggs are also peculiar. There is a large 
anterior dorsal ganglion, from which proceed 4 longitudinal nerve- 
stems ; these posteriorly first coalesce into 2 and afterwards ter- 
