Misci llaneous. -A 1 



111. J'uisnn-f/hni'ls. — Among the pluriccUular alveoli of the 

 salivary glands \vc find a c-crtain number of bulky pyrilorm cells, 

 wliifh are distinguished from the other gland-cells hy their affinity 

 for the acid stains. Studying these cells at different .stages, I 

 perceived that they form unieellular glands, which open into tho 

 salivary ducts by a short canal. These glands are situated ex- 

 clusively upon the three great trunks of tho excretory canals. 

 I consider these histological elements to be poison-glands ; tliey 

 arc, moreover, much more numerous in the species oi Arr/as than 

 in those oi Ixodes, a fact which explains easily enough the greater 

 degree of irritation caused by the bite of the former when compared 

 with that inflicted by tho latter. 



In the resting condition (that is to say, in individuals which have 

 been detached from their host for a certain time) the nucleus of 

 these cells is regular in shape, rounded, and sharply defined. At 

 the moment of secretory activity the nuclear membrane disapi)ears, 

 and the nucleus sends out irregular prolongations, especially on 

 the side of the apeiture of tho gland. These prolongations become 

 detached from the central mass, and break up into nuclear granula- 

 tions which are entirely identical with the venogcnous granules 

 observed in the poison-glands of Arthropods and snakes. 



The cytoplasm stains readily with eosin, and is finely granular. 

 Nevertheless, around the nucleus and the nuclear granulations it 

 exhibits a hyaline zone of slight plasmic density ; this zone 

 is more or less extensive, according to the bulk of the mass of 

 chromatin contained in it. The chromatic granulations appear to 

 dissolve in the cytoplasm, and modify it in order to produce the 

 toxic substances. 



It seemed to me interesting to notice these nuclear emissions, 

 which here undoubtedly play a highly important part in the phe- 

 nomena of secretion, and probably participate in the formation of 

 poison in the gland, as Launoy, in his researches upon poison-glands, 

 has shown to be the case. — Comj'tcs liendus, t. cxlii. no, o (Jan, 1*9, 

 1900), pp. 296-298. 



The Large Dermal Glands of the Sj^ecies o/Echinaster. 

 ]{y Dr. PuiLU'P Eauthels. 



In his work " Die Seestcrno des Mittelmeeres " (• Fauna und 

 I'lora des Golfes von Neapel,' lid. 24, 1S97) Ludwig speaks on 

 page 320 of the large dermal glands of the species of Ec/iinasttr ; ho 

 describes their occurrence especially in Echiuasiir se^^oisitus, CJray, 

 and says that in. their longest diameter the glands measured from 

 0*() to 0'8 mm. After the removal of the epithelium covering the 

 body he was already able to recognize the glands with the help of a 

 lens, by means of the white coloration in the largo meshes of the 

 cutis, by which each one is surrounded. They had sometimes a 

 rounded and sometimes a more elongate outline, or one in which 



