ZOOLOGY. 355 



ary tracfis of it in the male; antennse usually rudimentary ; eyes large 

 in tlie male, often excessively so, occupying nearly the whole head: 

 Pleotomus, Lamprophorus, Microphotiis, Lampyris, and Lamprorhiza. 

 (Condensed from J. R. M. S., vol. iii, pp. 777-770.) 



POLYZOANS. 



RELATIONS OF THE POLYZOANS. 



The Polyzoans form a type which, in the early days of zoology, was 

 regarded as a class of the radiate animals. Subsequently Milne Ed- 

 wards and others agreed that the type was most closely related to the 

 Brachiopods, and subsequent investigation of the embryology of the 

 two types confirmed this view. The question afterward came up as to 

 the relationship of both these types to others. Until quite recently 

 it was disputed by no one that the Brachiopods were true molluslvs,but 

 when anatomical and morphological investigations had revealed so 

 many differences they were dissociated from the typical mollusks and 

 segregated with the Tunicates under the name MoUuscoidea. Later 

 Morse claimed that the two classes in question were more closely related 

 to the worms than to the njollusks. Professor Allman has recently 

 reviewed the condition of our knowledge of the endoproctal Polyzoa,* 

 and confesses that while he still supports the molluscan relationshii)s of 

 the type, he was nevertheless obliged to confess that there were features 

 in which it closely approximated the worms. Among the most signifi- 

 cant of these is the existence of a pair of symmetrically placed gland- 

 like organs which open on the surface of the body in Loxommu, and 

 remind one of the segmental organs of the worms. In 187- Professor 

 Nitzsch i)roposed to differentiate the Polyzoans into two groups, dis- 

 tinguished by the opening of the anal cavity in one case outside of the 

 tentacular crown, and in the other case within the same. The former 

 group was named Ectoprocta and included almost all the known forms. 

 The latter group was named Endoprocta, and was at first framed spe- 

 cially for PedicilUna, but subsequently it was ascertained that not only 

 Pedk-nUna but TJniatcUa and Loxosoma also exhibited the same char- 

 acteristic ; and Professor Busk has lately made known a curious form, 

 to which he has given the name Ascojmlaria, found in the voyage of 

 the Challenger in deep water. It is the Endoprocta, according to Pro- 

 fessor Allman, that exhibit the closest connection with the vermes. 

 Loxosoma, it may be added, is a parasite of Gepliya^eans, and attaches 

 itself so firmly to the host that before Loxosoma had been described Mr. 

 A. M. Js^ormaii was led thereby to attribute its crown to a Gephyrean as 

 tentacular appendages of the tail of that worm. 



* Allman (G. J.)- Some recent additions to our knowledge of the stricture of the 

 Marine Polyzoa. Jour. Linn. Soc. Zool, vol. xv, pp. 1-8. 



