\7- SUMMARY OF CUBRENT RESEARCHES RELATING TO 



This furnishes an argument in favour of including Bothriomolus in the 

 family Bothrioplanidae. ilallez describes the two chief vessels or col- 

 lectors, the vessels of the second order, the capillaries and ciliated 

 funnels, and other details of the intricate system. 



Dalyellidse and Umagillidae.* — Bruno Wahl gives revised diagnoses 

 and classification of these two families of Turbellarians, which include 

 a number of interesting, in part parasitic, forms, such as Graffilla, Ano- 

 plodium, Syndesmis, Dallyellia, and Umagilla. One of the remarkable 

 points referred to is the absence of male gonads in Graffilla parasitica. 



Echinoderma. 



Polarity of Primary Oocyte of Asterias forbesii.f — Naohide Yafsu 

 finds that in this starfish the point of attachment of the primary oocyte 

 coincides neither with the animal pole as in Strong ylocentrotus, nor with 

 the vegetal pole as in Oerebrahdus. In this case, therefore, the longi- 

 tudinal axis of the germ-epithelial cell does not correspond to the egg- 

 axis or to the embryonal axis. 



North Pacific Ophiurans.J — H. L. Clark describes the collection in 

 the U.S. National Museum — a huge piece of work — dealing with 189 

 species, 129 new. There are 12 new genera. He calls attention to the 

 difficulty of classification, one of the reasons being our ignorance of the 

 growth changes. The number of arm spines and oral papillae often 

 increases with age. Jackson's law of " localised stages " finds many 

 illustrations, for the Ophiuran arm often reveals the characters of youth 

 at or near the tip of the arm. Another interesting matter is variation 

 in the extent of calcification, and in the extent of resorption of the 

 calcareous matter. An interesting account of the distribution is given. 

 One of the general results is that " Jordan's Law " of isolation does not 

 seem to have much application here. 



Genera of Recent ClypeastroidsJ — H. L. Clark discusses these 

 " cake-urchins " or " sand : dollars," and recognizes five families (for 

 fifteen genera) — Clypeastridse, Arachnoididee, Lagauidre, Fibulariidas, 

 and Scutellidse. " The Clypeastridge are almost certainly the nearest 

 of the families to the original stock, and it is not hard to believe that 

 the Laganidee have had a common ancestry with them. The Fibu- 

 lariidre seem to have been derived from the Laganidas, or from a near 

 ancestor, by a process of simplification. The Arachnoididse are certainly 

 an old stock beginning on or near the Clypeastrid branch and with no 

 near relatives at the present clay. The Scutellidee are quite a distinct 

 branch, though their origin is probably very near that of the Laganidaa, 

 if not identical with it." Such simplicity as is shown by Echinocyamus 

 and Fibularia, which cannot be considered primitive, is probably asso- 

 ciated with their small size. 



* Festschrift Richard Hertwig, ii. (1910) pp. 39-60 (2 pis. and 1 fig.). 

 t Annot. Zool. Japon., vii. (1910) pp. 217-21 (7 figs.). 

 J U.S. Nat. Mus. Bull. lxxv. (1910) pp. 1-302 (144 figs.). 

 § Anu. Nat. Hist., vii. (1911) pp. 593-605. 



