638 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



The differences wliicli obtain in the Eetitelariae, the Tubitelariae, the 

 Citigradae, the Laterigradse, the Saltigradse, the Plagitelariae, and the 

 Teriitelarige are nest fully described. 



All the glands consist of a secreting portion — glands in the strict 

 sense — which also serve as collecting cavities for the spinning material — 

 and of an efferent duct \\ hich opens to the exterior by a spool of varying 

 size. The true gland consists of a tunica propria and a more or less 

 high epitheliiun. The duct consists of a tunica propria, and of a low 

 epithelium (except in the aciniform and pyriform glands where there is 

 no epithelium) and of a thick tunica intima. The spinning spools 

 consist of a basal and an accessary piece. The upper and lower warts 

 are two-jointed, and the median one-jointed, except in the Mygalidfe 

 where there are three and two joints respectively. In addition to the 

 five glands already enumerated there are also lobate and cribrellum- 

 glands ; these are variously distributed in various groups, and the 

 Mygalidse have pyriform glands only. In the males the number of 

 tubuliform glands may be less than in the females, or they may be com- 

 pletely wanting. With the exception of the Mygalid^ no Spider has 

 less than three or more than six kinds of glands. 



The author has made a number of biological investigations, the chief 

 results of which are : the glandulaa aggregatae prepare the so-called 

 moist filaments from the moist droplets ; the tubuliform glands spin the 

 egg-cocoon ; the cribrellum-glands prepare the coiled tissue. The 

 lobate glands prepare the spinning material to catch the prey. The 

 pyriform glands form the seizing tissue and attach the separate filaments 

 to firm objects by means of the so-called disc of attachment. The 

 function of the aciniform and ampuUaceous glands is not yet known. It 

 is possible that several glands may take part in spinning a web round 

 the prey. 



Parasites of Spiders.* — Dr. P. Bertkau communicates some obser- 

 vations on the occurrence of Mermis in Tarenhda inquilina and the 

 resulting sterility of the host. Worm parasites Lave seldom been 

 observed in Arachnids, but the author has occasionally found them in 

 Salticus formicarius and Tegenaria atrica. In the species of Tarentula 

 above mentioned a large Mermis, probably M. albicans, was repeatedly 

 found. 



In autumn the mature sexes of this spider are to be found ; after 

 copulation both disappear. The females conceal themselves and lay 

 eggs ; the males die. When mature forms are found in May and June 

 they often contain a Mermis. Several cases are described, in one of 

 which the parasite measured 11*3 centimetres. In a male Tarentula govl- 

 taining this parasite the sexual function seemed to have been prevented. 

 It was caught in May, with palps full of encysted sjaermatozoa. Bertkau 

 thinks that copi;lation had been hindered for some nine months. The 

 act is followed by death ; the motive comes as usual from the internal 

 reproductive organs, not from the sperm-laden palps, but the presence 

 of a parasite may entirely alter the habit. 



New Acarid.f — Prof. B. Grassi and Sig. G. Eovelli describe a 

 peculiar Acarid, Podapolipus reconditus g. et sp. n., an abundant parasite 

 on the Coleopteron Aids (or Acis) spinosa. The jDarasite belongs to the 



* Verb. Nat. Ver. Preuss. Rheinl., xlv. (18S8) pp. 91-2. 

 t Bull. Sue. Entoinol. Ital., xx. (1888) pp. 59-63 (1 pi.). 



