4(52 SUMMARY OF CURRENT RESEARCHES RELATING TO 



numerous anil so Btrikiug that we cannot refuse to place this 

 enigmatical worm with the Chordata, of wliiclj he tentatively suggests 

 the following table : — 



Chordata — Hemichorfla[ta] (Entcropneusta). 

 Urochorda[ta] (Ascidians). 

 Cephalochorda[ ta] (A mpliioxus). 

 Vertebrata. 



Echinodermata. 



Cotton-spinner.* — In some further notes on Holothuria nigra'Prof. 

 r. Jctfrcy Boll gives a description of fresh specimens, and describes 

 some experiments with the colouring matter, which is dissolved out of 

 their bodies by alcohol ; this has the same characters as antedonin, but 

 has no distinctive absorption bands, or has them obscured by another 

 colouring matter which is richly deposited around the attached ends 

 of the Cuvierian tubes. As the ejected tubes owe their difference in 

 thickness merely to the differences in the packing of the threads, it 

 follows that tlie elongation of the threads is due to the uncoiling of 

 the connective-tissue fibres. The British species appears to be dis- 

 tinguished from the Mediterranean H. poli by the absence from its 

 suckers of the characteristic spicules. 



Echinodermata of Ceylon.f — Although Dr. A. Walter states that 

 this essay is a " Beitrag " to the paper by Prof. Bell on the same subject, 

 he makes several important additions to tlie fauna of Ceylon, from the 

 collection made by Hiickel in 1881-2. A specimen of Luidia macu- 

 lata with arms 220 mm. long was collected ; specimens of Toxopneustes 

 pileolus were, contrary to the statement of A. Agassiz, found to agree 

 remarkably with one another, and fourteen were collected ; on the 

 other hand, the fifteen examples of Hipponoe variegata varied remark- 

 ably. On the whole thirty-two species are known to the author (who, 

 like Bell, failed to enumerate Antedon reijnaudi, which was long since 

 described by Miiller and Troschel as coming from Ceylon), and nine 

 of these are first due to Hackcl and his collectors, though they are not 

 " new species." We may add that there is every reason to believe 

 that the number of known Holothuria will be shortly shown to be far 

 more than two ; Dr. Ondaatje has lately collected a specimen of Synapta 

 heseli measuring 7 feet in length. 



Ccelenterata. 



Development of Male Germinal Cells in Hydroids.j — Herr J. 

 Thallwitz comes to conclusions which are not quite the same as those 

 of some of his predecessors. In opposition to Korotneff and Bergh he 

 finds that the heads of the spenuatozoa arise from the nuclei of the 

 spermatoblasts, and not independently of them. He cannot agree 

 with de Varenne that the nucleus does not undergo change ; on the 



* Proc. Zool. Soc. Lond. for 1884 (188.^) pp. 563-5. 



t Jenaisob. Zeitschr. f. Naturvxiss., xviii. (1885) pp. 365-84. 



t Ibid., pp. 385-444 (3 pis.). 



