88 Miscellaneous. 



Sladeii ; but in opposition to his definition of the genus Sti/mcaster, 

 one of our species (S. sjnnosus, E. P.) presents a dorsal peduncle ; 

 the other (S. Edwardsi, E. P.) has only a simple tubercle, but each 

 of its arms bears seven spines upon its median dorsal line. The 

 Hijphalasteres {H. Antonii, E. P., and H. Parfaiti, E. P.) have their 

 adambulacral plates of normal form and not oblique relatively to 

 the furrow which they border ; the former has seven cribriform 

 organs, two of which are rudimentary, but there are for each arm 

 nine dorsal marginal jjlates, of which the last four are soldered to 

 their corresponding plates ; the second has nine cribriform organs. 

 The Pseudasteres exactly resemble Pentagonasteres with slightly 

 concave sides ; their cribriform organs are rudimentary and their 

 apical plate is large and heai-t-shaped. 



The nearest shore-relatives of the Porcellanasteridae are the Cteno- 

 disci of the I^orth Atlantic and the coasts of Patagonia. They live 

 at the following depths : — Porcellaaaster iaennis at 3000, Stifra- 

 caster Edwardsi at 3655, Hyphalaster Antonii at 2995, H. Parfaiti 

 at 4787, and Pseudaster cordifer at 4050 metres. 



Among the Pterasteridaj we have to place a perfectly new form 

 which we shall name Myxaster sol. All the Pterasteridae hitherto 

 known have short arms and a more or less pentagonal form. Myx- 

 aster sol has a broad flattened disk, round which radiate nine or ten 

 slender, elongated, flexible arms, which give the animal somewhat 

 the appearance of Solaster endeca. The dorsal marsupial sac so 

 characteristic of the Pterasteridae is, however, well developed and 

 closed as usual by five valves. The two examples collected by the 

 * Talisman ' were dredged off the coast of the Sahara, one at 1405, 

 the other at 1550 metres. This form seems to us to indicate a much 

 closer relationship than is usually admitted between Solaster, Kore- 

 tJirasfer, and the Pterasteridae. — Comj^tesBendus, Nov. 2, 1885, p. 884. 



Reprodaction of Freshwater Planarice hy Transverse Division. 

 With reference to a previous statement of his upon the above 

 subject (see ' Annals,' December 1885, p. 522), Dr. Otto Zacharias 

 calls attention to the fact that Dr. J. von Kennel had already 

 noticed the occurrence of the phenomenon in the freshwater Plana- 

 rians of Trinidad (Arb. zool.-zoot. Inst. Wurzb. Bd. vi. 1883). Dr. 

 von Kennel says : — " All the freshwater Planarise that I found are 

 remarkable for their very small size, but one of them, from a small 

 pond on the east coast of the island, also by an interesting biological 

 peculiarity — -it multiplies normally by transverse division, so far as 

 I know the first certain example among the Dendrocoele Planarians. 

 So far as could be ascertained from the living animal, no sexual 

 organs are present, or they are in a very primitive state of develop- 

 ment. A short distance behind the mouth eye-si^K)ts make their 

 appearance as new formations, probably in connexion with the 

 development of a new brain ; also a new oesophagus with a buccal 

 orifice ; a slight depression of the epidermis indicates the future 

 place of division, and I frequently saw the breaking into two indi- 

 viduals under the microscope." — Zoologischer Anzeiger, Nov. 23, 

 1885, no. 209, p. Qm. 



