148 SUMMARY OF CURRENT RESEARCHES RELATING TO 



budding, as seen in Willey's Merocercus ; (3) external budding, as ex- 

 emplified in the species of Polycerciis and Staphylocystis, described by 

 Haswell and Hill ; and (4) parthenogenetic reproduction, uniquely 

 illustrated in IJishia partfmiogenetica Southwell and Prashad, an adult 

 tapeworm of doubtful affinities. J. A. T. 



Rhabdites of Turbellaria. — Marcel Prenant- {^Arcli. Zool. Exper., 

 1919, 58, 219-50, 1 pL, 12 figs.). These bodies are formed of one or 

 more protein substances (with sulphur and phosphorus) combined with 

 calcium. They are almost certainly nucleoproteins, arising from the 

 degeneration of the nuclei, and may be either excretory or reserve pro- 

 ducts. Their formation is preceded, in many cases at least, by nuclear 

 buds and degeneration. In the epidermis of Polyclads their formation 

 from degenerate nuclei is direct ; they have the value of nuclei ; their 

 individualization is due to amitosis or to budding. In the epidermis of 

 Triclads and Ehabdocoelids the rhabdites arise in superficial corpuscles, 

 probably the basal corpuscles, and their appearance is associated with 

 the degeneration of adjacent nuclei. In Fecampia erythrocephala, about 

 the time of encystation and of oviposition, there is an abundant pro- 

 duction of rhabdites, followed by their disappearance. There is 

 probably in most cases an actual waxing and waning of rhabdites. In 

 Prosthiostomum siphunculus there are rhabdites in the parenchyma, the 

 third case among Polyclads. J. A. T. 



Reactions of Proboscis of Planaria albissima. — W. A. Kepner 

 and Arnold Rich {Journ. Exper. Zool., 1918, 26, 83-100, 10 figs.). 

 A proboscis severed from its adjacent ganglion still shows some reaction 

 by disturbed movements within the sheath. In most cases a proboscis, 

 thus separated from the central nervous system, underwent auto- 

 amputation while lying within the sheath. Sometimes this did not 

 happen without a disturbance of the thigmotatic conditions within the 

 sheath. In all cases, however, the disturbance of the thigmotactic 

 conditions of the sheath so excites the proboscis that, without the 

 inhibitory control of the adjacent ganglia of the central nervous system, 

 the proboscis suffers auto-amputation, and acts as an independent reflex 

 " organism." It can carry out the three co-ordinated muscular move- 

 ments involved in food-ingestion, provided that its entire musculature is 

 intact. It cannot distinguish between food and non-food, for that 

 requires the functioning of the central nervous system. J. A. T. 



Incertae Sedis. 



Transverse Fission in Phoronopsis. — J. D. F. Gilchrist {Quart. 

 Journ. Micr. Sci., 1919, 63, 493-507, 1 pi.). This Phoronid has been 

 observed to reproduce asexually by transverse division of the body. The 

 division occurs in the muscular region, and the detached part is capable 

 of locomotion. It divides a second time below the lophophore, which is 

 thrown off and disintegrates. The remaining part, after moving about 

 freely, develops an anterior projection (epistome ?), a lophophoral ridge, 



