ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 491 



solution. By boiling with acids, or by digestion with saliva or 

 diastase, the substance is converted into dextrin and grape-sugar. 



Rhodope veranii.* — Professor L. Graff gives an account of this 

 form, which was regarded by Schultze as a Turbellarian, and named 

 Sidonia elegants; he has been able to demonstrate that it is not 

 a worm, but the Nudibranch long ago described by Kolliker under 

 the name of Rhodope veranii. The largest examples are about 4 mm. 

 long, with a breadth of ^- mm. 



The integument consists of a single stratum of cylindrical epithe- 

 lial cells, and is pretty closely invested by long cilia ; this integument 

 is pigmented, and a figure of the curious arrangement of the colour, 

 under what the author regards as its typical form, is given. Cal- 

 careous spicules, of some size, are to be found under two different 

 forms, embedded in the parenchyma of the body. The mouth lies at 

 the anterior end, but is sometimes held dorsally ; the cavity into 

 which it leads is provided with closely appressed small papilla;, but 

 there is no indication of anything like a radula. After some account 

 of the other parts of the digestive system, of the nervous system, and 

 of the generative apparatus, Dr. Graff states that, like Kolliker, he 

 searched in vain for any indication of a heart or blood-vessels. The 

 numerous small oval corpuscles which fill the coelom were suspended 

 in a colourless fluid, which appears to be set in motion by the move- 

 ments of the body, or the contractions of the enteron. The author 

 was, however, enabled to discover a water-vascular system similar to 

 that of the Platyhelminthes. Strong magnification revealed actively 

 moving flagella, scattered through the body, and similar to those 

 which are found in the excretory system of various Vermes. Each 

 flagellum is continued in a vesicular enlargement, and by its widened 

 base completely closes the ciliated funnel, the free end of the flagellum 

 being directed towards the efferent canal. No exact information can be 

 given as to the branchings of the excretory system, or as to the 

 character of its orifices. 



The absence of gills, buccal mass, and radula, as well as of a 

 vascular system, proclaims Rhodope to be the very lowest of all known 

 Nudibranchs ; at the same time it is distinguished from the allied 

 Turbellaria by its anus, by the structure of its generative organs, its 

 central ganglia, and its sensory apparatus. Rhodope must not, 

 however, be supposed to have been derived from the present specialized 

 Dendrcccela, but from a group of Rkabdocoelida, to which, in his 

 forthcoming Monograph of the Turbellaria, the author intends to 

 apply the term Alloioccela ; this group will contain Vorticeros and 

 others, and will be distinguished from the Acoela and the true 

 Rhabdocoela by characters which will, we think, be better understood 

 when that subject comes before us. 



Molluscoida. 



Test-Cells in Ascidian Ova.f — These cells, so characteristic of 

 the ova of Tunicates, obtained their name from the belief that they 



* Morph. Jahrbuch, viii. (1882) pp. 73-83 (1 pi.)- 

 t Zool. Anzeig., v. (1882) pp. 356-7. 



