442 SUMMAEY OF CURRENT RESEARCHES RELATING TO 



to external and internal conditions. It seems to the investigator that 

 the eye functions, before the otocyst, as an equilibrating organ. 



Macrura of the ' Hassler ' and ' Blake. ' * — E. L. Bouvier makes a 

 preliminary report on some of the undescribed free-swimming Macrura 

 of the American expeditions ' Hassler ' and ' Blake.' Among the Penaeidae 

 the most interesting type is N eopenceopsis paradoxus g. et sp. n., which 

 has no exopodites on the last two pairs of limbs. Another instructive 

 form is Arcliipenceopsis vestitus g. et sp. n., related to Penaiopsis and 

 ffemipenceopsis. A transition between Artemisia and Haliporus is repre- 

 sented by Parartemisia g. n. Among the Stenopidaa there is a new 

 species of Richardina {R. inermis), which differs from the other three 

 species in being without an armature of spines. 



Meristic Variation in an Isopod.f — Seitaro Goto reports the 

 occurrence of a supernumerary thoracic segment (eight instead of seven) 

 in a species of Ligia. The occurrence of a supernumerary segment in a 

 Malacostracan is very rare. 



Hepatic Tubes of Anilocra frontalis.! — A. Guieysse finds that in 

 this Isopod the physiologically enigmatical " hepatic tubules " have 

 peculiar cells in which the lobed nucleus enters into close connection 

 with the cytoplasm. 



Commensalism of Two Isopods.§ — Carmelita Rossi calls attention to 

 the occurrence of Jcera Tcroyeri M.-Edw. on the body of SpJmroma 

 serratum Fabr. The occurrence of a species of Jais {J. pubescens) on 

 another Splicer oma (S. gigas) has been previously recorded. The 

 author thinks that parasitism is out of the question, and points out 

 that the integument and limbs of Sphmroma serratum bore a notable 

 number of Vorticellids and other Infusorians, which form the favourite 

 and ordinary food of Jcera. Therefore the association is nearer com- 

 mensalism (convivenza). 



Nervous System of Copepoda.|| — 0. 0. Esterly communicates some 

 facts regarding the peripheral and central nervous system in fresh-water 

 Copepoda. Each aasthetask-bearing joint of the anterior antennas of 

 both male and female of Diaptomus contains a group of cells which stain 

 with methylen-blue. It can be seen that peripheral processes arise from 

 such cells, and unite into a single strand to enter the assthetask. The 

 so-called tactile bristles on the antennas do not show such characters, but 

 in the furcal bristles of a species of Cyclops, structures, probably nervous, 

 have been found. The rostrum of Diaptomus is probably sensory in 

 function. In several cases bipolar cells occur far back in the abdomen, 

 whose central processes unite before entering the thorax and pass as a 

 single fibre far forward towards the brain. 



Halocyprids of San Diego. If — Chancey Juday reports on the 

 plankton Ostracods of San Diego belonging to the family Halocypridae. 



* Comptes Rendus, cxli. (1905) pp. 746-9. 

 f Annot. Zool. Japon, v. (1906) pp. 279-81 (1 fig.). 



X Bull. Soc. Philom. Paris, v. (1905) pp. 207-11. See also Zool. Zentralbl. xiii. 

 (1906) p. 207. § Zool. Anzeig., xxx. (1906) pp. 107-9. 



|| Univ. California Publications, iii. No. 1 (1906) pp. 1-12 (2 pis.). 

 H Op. cit., No. 2 (1906) pp. 13-38 (5 pis.). 



