clxxxvi GENERAL SUMMARY OF SCIENTIFIC AND 



Philadelphia, while the anatomy of Tcenia mediocanellata 

 a tape-worm more common in Europe than T. solium is 

 discussed by Dr. Welch in the Quarterly Journal of Micro- 

 scopical Science. 



A synopsis of North American fresh-water leeches, with 

 descriptions of some new species, with figures, has been pre- 

 pared by Professor A. E. Verrill for the Report of the United 

 States Commissioner of Fish and Fisheries. 



The Crustacea have been studied anatomically by Claus, 

 in an illustrated essay on the higher Copepoda, in Siebold 

 and Kolliker's Zeitschrift. The early condition of the nerv- 

 ous system of the king - crab [Limulus) has been described 

 by Dr. A. S. Packard. Instead of the cephalothoracic ganglia 

 being united to form a ring around the oesophagus, they 

 are in the larva separate, five pairs of large ganglia corre- 

 sponding to the five anterior pairs of limbs. The brain of 

 the king-crab differs remarkably from that of the normal 

 Crustacea i. e.,the lobster and crab in sending off no anten- 

 n al nerves,- but only two pairs of optic nerves, there being, 

 in fact, no antennoe in Limulus. While there is a general 

 analogy in the form of the anterior portion of the nervous 

 chord of Limulus to that of the spiders and scorpions, it 

 does not prove that the king-crab is an arachnid, for there 

 are other remarkable differences that forbid our placing the 

 king-crab among the arachnids, and they should be regarded 

 as very aberrant Crustacea. Packard also described certain 

 organs in Limulus as probably renal in their nature, and 

 perhaps homologous with the green glands of the normal 

 Crustacea. 



Additional facts, regarding the metamorphoses of the 

 spiny lobster (Palinurus) of the Mediterranean have been 

 discovered by Gerbe. By his study of the Phyllosoma, or 

 larva state of the Palinurus, he concludes that in the higher 

 Crustacea the peripheral portion of the arterial system very- 

 slowly arises, and during the early stage of the change the 

 bloodvessels ramify among the tissues like the roots of a 

 plant. 



In descriptive crustaceology we have a " Synopsis of 

 the Higher Fresh-Water Crustacea of the Northern United 

 States," by Professor S. I. Smith, containing full descrip- 

 tions of a number of interesting forms, including Palcemon 



