ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 609 



{the stem-form of the Peromedusas) has the four interradial tentacles 

 converted into rhopalia; Procharagma (the stem-form of the Cubo- 

 medusaa) has the four perradial tentacles so converted ; while in 

 Ephyra (the stem-form of the Discomedusae) all eight are so con- 

 verted. 



The first order is broken up into the Pericolpidse and the Peri- 

 phyllidae ; the second into the Charabydeidfe and the Chirodropidse ; 

 and the third into the Carmostomfe, Semostomfe, and Ehizostomas. 

 The first two, with the Stauromedusse, form the sub-legion Tesseronige, 

 in which the umbrella is hollowed out, conical or quadrilaterally 

 pyramidal, the gonads developed centrifugally, the subumbral wall 

 provided with four wide gastric pouches, and the sensory organs none 

 or four. In the Ephyronise the umbrella is flattened and discoid, the 

 gonads developed centripetally, and the sensory organs at least eight 

 in number. They all pass through an Ephyra, as the others do 

 through a Tessera form. 



The Discomedusse.* — In a further communication, Professor 

 Haeckel gives the following arrangement of the sub-orders of this 

 division : — 



1. CarmostomcB. — Mouth-tube simple, no buccal arms ; central 

 mouth simple, quadrilateral ; radial pouches broad, no circular canals ; 

 four or eight gonads ; tentacles solid, generally short. Here we find 

 the families EphyridaB and Linergidse. 



2. SemostomcB. — Mouth-tube divided into four perradial folded 

 arms ; central mouth simple ; radial pouches broad and without a cir- 

 cular canal, or narrow and with one ; four gonads ; tentacles hollow, 

 generally long. Here we have the Pelagid^, Cyaneidse, FlosculidEe, 

 and Ulmaridfe. 



3. Rhizostomce. — Mouth-tube replaced by eight adradial arms with 

 numerous sucking mouths ; central mouth obliterated ; radial canals 

 narrow, always branched ; a circular canal ; four gonads ; no tentacles. 

 This suborder includes the families Toremnidte, Pilemidae, Versuridae, 

 and Crambessidse. 



The author gives a phylogenetic table to show the genetic relations 

 of these different groups. 



Porifera. 



Observations on Sponges.f — F. E. Schulze's tenth communication 

 is dedicated to Gorticium candelcibrum 0. Schmidt. 



After a short history of the genus and of the seven species now 

 referred to it, the author gives a general account of the species he 

 has especially studied. With regard to histological details, he points 

 out that they are easier to study than in most sponges, on account of 

 the cartilaginous consistency of its hyaline substance. In many, and 

 especially in young examples, it is quite easy to make out a uni- 

 laminate layer of pavement epithelium investing the whole of the 

 free surface of the body. The rather high and often cubical cells 



* Loc. cit., pp. 51-4. 



t Zeitschr. f. wiss. Zool., xxxv. (1881) pp. 410-31 (1 pi.). 



