420 SUMMARY OF CURRENT RESEARCHES RELATING TO 



synonymy, and has taken pains to give an accurate description and good 

 figure of each species, so that it ought not to be difficult in future to 

 determine the animals of this family met with in lakes and ponds. 

 This revision has necessitated a number of changes in classification in 

 order to bring the generic and specific names into consonance with the 

 recognised rules of nomenclature. In accordance with these rules the 

 family is divided into the two genera, Diurella and Raitulus, as having 

 historical precedence over the names of Caclopus, Raitulus and Masti- 

 goc&rca, which they replace. The genus Diurella comprises those 

 Rattulidae having two equal, or nearly equal toes which were formerly 

 called Raitulus and Ccelopus, whilst the genus Rattulus contains those 

 animals having a single long toe with usually some small sub-styles, and 

 formerly called Mastigocerca, Though these changes in names are 

 troublesome, and may at first produce a little confusion, they are 

 historically correct and must be accepted. One can only regret that 

 the late C. T. Hudson did not avail himself of the unique opportunity 

 of putting the nomenclature right when writing his great work, The 

 Rotifera. In the present monograph thirty-six species are recognised 

 as good, of which two are described as new, and a list of seventeen 

 doubtful or insufficiently described species is added at the end. The 

 two new species are named : Diurella weberi and D. dixon-nuttalli. 



Echinoderma. 



Parthenogenetic Larvae of Asterias glacialis.* — Yves Delage 

 obtained parthenogenetic larvae experimentally by the action of carbon 

 dioxide on unfertilised eggs. They attain a stage approaching meta- 

 morphosis, exhibiting rosette and apical disc, and having five lobes 

 representing the five arms, containing terminal plates having the form 

 of broad fenestrate laminae. Their development was very slow — it lasted 

 for more than three months. The few survivors which reached this 

 stage were lost by accident when they were full of life, and there was 

 no reason to suppose they were not in a state to reach complete develop- 

 ment. Artificial feeding with a pure culture of Chlorellse, enabled 

 the author to attain the success he reached. 



Parental Care in Echinoderms.f — H. Ludwig recalls attention to 

 a case described by Th. Mortensen.} In Hgpsiechinus coronatus, a deep- 

 water North Atlantic Echinoid, the eggs and embryos are sheltered by 

 spines around the apical disc of the female. 



Ccelentera. 



Medusae from Maldive Islands. § — H. B. Bigelow concludes, from 

 the results of a collecting trip to these islands, that the fauna as repre- 

 sented in the Medusae, though showing a general resemblance to that 

 of the Tortugas in the Atlantic and Fiji in the Pacific, has no recent 

 relationship to either of these. The general resemblance of the three 



* Arch. Zool. Exp., ii. (1904) pp. 27-42 (1 pi.). 



t Zool. Anzeig., xxvii. (1904) p. 423. 



% Danish Jngolf Exp., iv. (1!)03). 



§ Bull. Mua. Compar. Zool. Harvard, xxxix. (1904) pp. 245-G9 (9 pis.). 



