780 SUMMARY OF CURRENT RESEARCHES RELATING TO 



from one side to the other, and enclose a canal open in front and 

 behind, and having for its floor the dorsal wall of the body with the 

 elytra and the "branchial" tubercles. These authors regard the 

 oxygenation of the perivisceral fluid as taking place through the thin 

 integument covering the scale-tubercles and the tubercles at the bases 

 of the dorsal cirri, and have observed the scales to be subject to 

 rhythmical movements, by means of which a current of water is driven 

 continually over the dorsal surface, thus renewing the water in 

 contact with the "branchiae." In species in which the felt-like 

 dorsal covering does not exist, this function would appear to be in 

 abeyance ; and in Polynoe and allied genera, so far as Mr. Haswell 

 has observed, the elytra remain perfectly motionless while the animal 

 as a whole is at rest. 



The sexual products reach the exterior through apertures in the 

 bases of the parapodia ; and the ova are carried by ciliary action to 

 the under surface of the scales, where they remain, adhering by means 

 of a viscid matter, till the embryos are well advanced. Impregnation 

 probably takes place while the eggs are in this situation. 



Phosphorescent Organs of Tomopteris.*— In two new species of 

 this genus of worms, described, from near the West Coast of Equa- 

 torial A.frica, by Dr. E. Greef, under the names T. Bolasi and 

 T. Mariana, the so-called " rosette-shaped organs " are represented not 

 as eyes or glands as has been hitherto done, but as organs for pro- 

 ducing light. In these species they are formed on the middle of the 

 " rudder " of the parapodia as well as on the floats. 



Under low magnifying powers they are seen to form sac-like 

 spaces, enclosing a globose yellow oily mass which ultimately proves 

 to be made up of a number of yellow tubes aggregated like the seg- 

 ments of an orange, thus producing the well-known rosette-like 

 appearance. In T. Mariana the organs differ according to their 

 position ; those in the floats have the ordinary rosette-characters, but 

 those of the rudders of the two front pairs of parapodia form two 

 large organs occupying almost the entire breadth of the foot, lying 

 near the inner wall of the ventral part ; they are rosettes of a deep 

 orange-yellow colour, enclosed in transparent rosette-shaped sacs. 

 The tubes composing the rosette are filled with a granular substance. 

 The organs are supplied with nerves on which ganglia occur over the 

 sacs ; from these ganglia proceed fine nerves which penetrate the 

 sacs and reach the rosettes. Each of the segments, 6 to 11 in 

 T. Bolasi and 8 to 11 in Mariana, exhibits a segmental organ near 

 the point of projection of the parapodium from the body ; it consists 

 of a short curved ciliated canal with a large internal and somewhat 

 smaller ventral external opening ; the former has a frilled margin, 

 the latter has sharp edges. On the ventral side of segments 4 and 5 

 in sexually mature females occur a pair of transverse genital slits. 



Priapulus bicaudatus.j — E. Horst distinguishes in the cuticle of 

 this Gephyrean two layers, the outer of which is thin and homo- 



* Zool. Anzeig., v. (1882) pp. 384-7. 



t Niederlanrl. Arch. f. Zool., Suppl. Bel., i. (1882) Gephyrea, 13 pp. 



