562 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Cribriform Cretaceous Polyzoa.* — W. D. Lang has revised the 

 Cretaceous Polyzoa usually placed in GribriUna and similar genera. 

 As in other fossil Polyzoa, each form is a colony (" asty "), composed of 

 individuals (" oecia "), incrusting other objects in free unilaminar or 

 bilaminar sheets, in cylindrical tree-like forms, or sometimes in multi- 

 laminar masses. The oecia are Cribrimorphs and Steginomorphs, 

 and are derived from Membranimorphs, or Cheilostome Polyzoa, 

 with a box-like cecium, of which the uppermost side (front wall) 

 has on it an oral rim (the "termen") which may be beset with 

 spines. The termen includes the aperture. Outside the termen the 

 skeleton is calcareous, within the termen it is chitinous. The evo- 

 lutionary aim in the development of all families appears to be the 

 disposal' to the best advantage or least detriment to the organism of 

 superfluous calcium carbonate. Ontogenetic stages of individual 

 oecia can sometimes be seen at the growing edge of the colony, and the 

 ontogeny may be used to corroborate the view taken of the phylogeny. 

 Astogeny, or' the growth of the colouy itself, is a useful guide, and in 

 fossil Polyzoa has this advantage, that each successive stage is left 

 behind, and not, as a rule, covered over or obscured by further growth. 



Kotatoria. 



South African Bdelloids.f — W. Milne describes 3Ionoceros fakatus 

 g. etsp. 11. (the generic name will require rectification), type of a new 

 family of Bdelloid Rotifers, having on the penultimate segment of the 

 foot one spur only. There are four toes, each in a separate external 

 sheath, and the rostrum is fully developed. The corona is inconspicuous 

 or obscure. The jaws are abnormal. Two small circular arrangements, 

 with not the slightest semblance of pedicels, situated on a prone face, 

 represent the corona in Fhilodina. The gullet is extremely short. 

 The most striking feature is the posterior aspect of the foot, with its 

 four great sickle-shaped toes and the large spur, looking, when all 

 planted downwards, as if supported on a banana-like bunch of props. 

 The author describes Didymodactylos carnosus sp. n., nine new species 

 of Philodiita, and three new species of Macrotrachela. 



Echinoderma. 



Parental Care in Holothurians^ — H. Ohshima describes a hitherto 

 unrecorded case of brood-caring in Holothurians. Among many speci- 

 mens of Fsendocucumis afrkanm he found three which contained young, 

 in all cases within the body-cavity of the mother. The young were all 

 practically at the same stage of development, the size varying from 

 1-4 mm. by 0-6 mm. to 10 mm. by 2-5 mm. The colour was a light 



* Ann. Mag. Nat. Hist., xviii. (1916) pp. 81-112. 



t Journ. Quekett Micr. Club, xiii. (1916) pp. 47-84 (5 pis.). 



X Annot. Zool. Japon, ix. (1916) pp. 121-4 ^1 fig.). 



