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THE VOYAGE OE H.M.S. CHALLENGEE. 
distinct from the other known genera, and what its exact position is, cannot be determined 
without more information as to the structure than is given in Gray’s short description. 
In 1871 Dr. R. 0. Cunningham, in his Report upon the collections made during the 
cruise of the “ Nassau,” ^ described a remarkably large Ascidian from the Strait of 
Magellan under the name of Goodsiria coccinea. This species, which Cunningham 
regarded as a Social Ascidian, forms an elongated massive colony, sometimes more than 
2 feet in length. The rounded Ascidiozooids are imbedded in the test, and are not 
divided into thorax and abdomen. I have examined the “ Nassau ” specimens in the 
British Museum, and the species was obtained again by the Challenger, consequently this 
form is well known to me. It is certainly distinct from the genus Thylacium, and it 
cannot be compared with the imperfectly known Oculinaria., Goodsiria may therefore 
be retained provisionally as a distinct genus, although it ought to be remembered that it 
may possibly be identical with Qpulinaria, Gray. 
Giard in 1874 described ^ two new genera of Ascidians from the French coast, 
Polystyela and Synstyela, which he regarded as being allied not to the Social Ascidians 
(Clavelinidse), but to the' Cynthiidse and especially to the genus Styela. Polystyela 
lemirri is an incrusting species consisting of a common basal part above which the 
Ascidiozooids project to a height of from 4 to 6 mm. In this respect it agrees with the 
genus Thylacium, and Giard does not point out any differences between the two forms. 
As, however, Giard was acquainted with Carus’s genus, the probability is that the two 
are distinct, and that Polystyela differs from Thylacium in having no distinct abdomen 
in the Ascidiozooids. Giard was of opinion that reproduction by gemmation was 
probably carried on, but he had not determined the matter conclusively. The second 
genus, Synstyela, is characterised by having the Ascidiozooids depressed and not pro- 
jecting above the upper surface of the colony. Alder’s Thylacium variegatum would 
therefore, as was suggested above, naturally find a place in this genus. Giard speaks of 
his species as being of a red colour, while Alder’s Thylacium variegatum is shaded wdth 
flesh colour and red : possibly they may be the same species. If so, it should be called 
Synstyela variegata (Alder). 
Heller,® writing in 1877, divided the family Cynthiidse into two groups — the Mono- 
cynthise, including all the ordinary Cynthiidse, and the Polycynthise, comprising the 
three genera Thylacium, Polystyela, and Synstyela. He therefore included these forms 
amongst the Simple Ascidians. Since that date no further attempt has been made to 
classify this curious little group of Ascidians. 
There can be no doubt that the family Polystyelidse is allied to the Styelinse amongst 
Simple Ascidians, and especially to the genus Polycarpa, Heller. The condition of the 
test 'in some forms, the shape of the Ascidiozooid in others, and the structure of the 
^ Trans. Linn. Soc. Land., vol. xxvii. p. 465. ^ /rang., Lille, 1874, p. 432. 
® Uiitersuchungen iiber die Tunicaten des Adriatischen und Mittelmeeres, Abth. 3, Wien. 
