198 SUMMARY OF CURRENT RESEARCHES RELATING TO 



line towards or away from a single source of light and at right angles to 

 the line connecting two lights of equal intensity. The experiments go 

 to show that the " instinctive " movements of these animals are phenomena 

 of automatic orientation (heliotropism), and a function of the constant 

 intensity of light. The exact expression of the function is the Bunsen- 

 Roscoe law of photo-chemical action. 



Maxillary Gland of Cypridina hilgendorfi.* — Naohide Yatsu 

 describes the minute structure of the group of unicellular glands which 

 forms the maxillary gland. The gland-cells are not differentiated into 

 gland proper and duct. There are two kinds of elements — raucous, with 

 granular cytoplasm ; and yellow gland-cells, with fibrillar cytoplasm. 

 The yellow secretion, which emits light, is in the form of coarse, 

 somewhat angular granules. There is no common reservoir for the 

 gland-cells, but the lower part of each gland-cell functions as a temporary 

 reservoir of the secreted products. 



Nematohelminthes. 



New Nematode from Partridge.f — C. Rodriguez Lopez-Neyra 

 describes Oyrnea seuratii sp. n. from the gizzard of the red partridge 

 {Caccabis rufa). The genus, one of the Spiroptera, occurs in burrows in 

 the median tunic of the gizzard, between the muscle and the horny 

 lining, and is characterized by the displacement of the vulva towards the 

 posterior end of the body. The body of the new species is robust, 

 translucent white, with a finely striated cuticle, with two strong lateral 

 lips besides a dorsal and a ventral. A contrast is made between the two 

 sexes, and between the new species and the allied C. eurijcerca Seurat. 



Platyhelminthes. 



Tapeworms of Reptiles. J— E. Rudin describes eleven species of 

 IchthyotsEuiidae from reptiles, discusses their common characteristics, 

 and gives a sketch of a natural classification of the family. He deals 

 with eight new species of Ophiotaenia, and two of Acanthotaenia, besides 

 0. racemo^a. Altogether there are now known thirty-nine Ichthyotse- 

 niidffi from reptiles and amphibians. They are Tetraphyllids with 

 small head, with sessile suckers without appendices ; the apical sucker 

 may be present, absent, or rudimentary ; there is no rostellum ; they are 

 confined to fishes, amphibians, and reptiles. The family includes six 

 genera : — Ichthyotsenia, Choanoscolex, Batrachotaenia g.n. Crepidobothrium, 

 Acanthoisenia and Ophiotaenia. Many details in regard to the minute 

 structure of the new species are communicated. 



Dibothriocephalus parvus Stephens. § — F, Zschokke has made a 

 study of this tapeworm from man, which J. J. W. Stephens described 



* Journ. Morphology, xxix. (1917) pp. 435-40 (4 figs.). 



t Comptes Eendus, clxvi. (1918) pp. 79-82 (2 figs.). 



1 Rev. Suisse Zool., xxv. (1917) pp. 179-381 (3 pis. and 26 figs.). 



§ Rev. Suisse Zool., xxv. (1917) pp. 425-40. 



